Cycloaliphatic sulfides

ABSTRACT

CYCOALKANE BIS(ALKYLSULFIDE) COMPOUNDS OF STRUCTURE   (R1-S-),R2,(R1-S-R&#39;&#39;-)CYCLOHEXANE (I) AND   BIS(R1-S-)HEXAHYDRO-4,7-METHANOINDAN   WHERE R1 IS HIGHER ALKYL, R2 IS H OR LOWER ALKYL AND R&#39;&#39; IS LOWER ALKYLENE AND THE USED OF THESE COMPOUNDS IN POLYOLEFINS. AS ANTIOXIDANT-SYNERGISTS.

United Smtes atent o1 3,652,680 Patented Mar. 28, 1972 ABSTRACT OF THEDISCLOSURE Cycloalkane bis(alkylsulfide) compounds of structure R2 RlSQR'SRl and 315%SR1 where R is higher alkyl, R is H or lower alkyl and Ris lower alkylene and the use of these compounds in polyolefins asantioxidant-synergists.

It is customary to stabilize polyolefins, particularly polypropylene,against oxidative degradation by incorporating in the polyolefins asmall amount of a phenolic primary antioxidant and a sulfur-containingsecondary antioxidant or synergist. The sulfide synergists now usedalmost exclusively are dilauryl thiodipropionate (DLTDP) or distearylthiodipropionate (DSTDP).

These known thiodipropionate esters DLTDP and DSTDP suffer from the factthat they are gradually leached out of polyolefins by hot water,particularly hot water containing soap or detergents. This gradual lossof stabilizer results in premature deterioration (embrittlement andcracking) of polyolefins when they are used for hot water pipe andtubing applications and as components in automatic laundry and dishwashers, Vaporizers and other hot water equipment.

The compounds of this invention are cycloalkane bis (alkylsulfides)having the general structures I and II shown below, where R is higher (042 straight-chain alkyl, R is H or lower (C -C straight-chain orbranched alkyl and R is lower (C -C straight-chain or branched alkylene.These compounds exhibit high activity as antioxidant-synergists.

R18 R'SR1 R18 SR They are superior to the thiodipropionates inresistance to hot water leaching and have excellent compatibility withpolyolefins.

The compounds of the invention are readily prepared from commerciallyavailable cyclic diolefins, H S and higher molecular weight monoolefinsas illustrated by the following three equations:

(or 4)(octadecy1tl1io) cyclohexane (see note) C 3 CH2SC15H2,9-bis(hexadecylthlo)-p-methine his (2(01' 3), 5(or 6)-hexadecylthl0)-octahydrol,7-Inethan0lndene (dipentene or d-limonene)(dicyelopentadlene) (see note) All the above reactions occur in thepresence of conventional free radical catalysts such as ultravioletlight, gamma radiation, peroxides and azo compounds. The followingexample, corresponding to Equation 1 above, illustrates the generalpreparative procedure which can be used to make the compounds of theinvention.

PREPARATIVE PROCEDURE The liquid-phase reaction of 4-vinylcyclohexene-lis carried out with excess H 8 in the presence of ultraviolet light from15 watt germicidal lamps to produce vinylcyclohexene dimercaptan (Bmercaptoethyl 3 (or 4)- mercaptocyclohexane), 979/l.25 mm. in highyield.

A solution containing 13 grams (0.073 mol) of vinylcyclohexenedimercaptan and 37 grams (0.146 mol) of octadecene-l in 300 cc. ofmethyl propyl ketone is maintained at about 5 C. While irradiating at47.5 watts with a Nester/Faust ultraviolet lamp for 5 hours. Fltrationof the precipitated solid gives 25 grams (50%) of the desired product,M.P. 67-695". Recrystallization from methyl ethyl ketone gives a softwaxy white crystalline product, M.P. 7l72 C.

Analysis.-Calculated for C I-1 C; (percent): C, 77.57; H, 13.02; S,9.41. Found (percent): C, 76.90; H, 12.95; S, 9.48.

The preferred compounds are the vinylcyclohexene derivatives III (IJH CHS R (III) where R is C -C straight-chain alkyl. R may be a mixture ofalkyls as obtained for example by reacting the dimercaptan fromvinylcyclohexene with commercially available mixtures of highermolecular Weight normal alpha olefins, e.g., C H and C H mixtures.Particularly preferred compounds are those WhCI'i R is l1-C12H 5, n-C H11-C18H37, n-C H41, and n-C H These are white, crystalline, low meltingsolids, easily mixed into polypropylene and polyethylene resins byconventional methods such as dry mix-extrusion.

The compounds of the invention are further characterized by the meltingpoints shown below:

1- [5- (dodecylthio) ethyl] -3 (or 4) -dodecylthiocyclohexane.

1- [13- (hexadecylthio) ethyl] -2 (or 4 -hexadecylthiocyclohexane.

l- 3-( octadecylthio) ethyl] -3 (or 4) -octadecylthiocyclohexane.

1- [/3- eicosylthio ethyl] -3 (or 4) -eicosylthiocyclohexane.

1 [B' (C22 28 "3 (or -C22 2 -thiO- cyclohexane.

2,9-bis (hexadecylthio) -p-menthane.

2,9-bis (octadecylthio) -p-methane.

bis (2 (or 3), 5 (or 6) -hexadecylthio)-octahydro 4,7-

methanoindene.

The compounds of the invention have low toxicity which is of value whenused in polyolefin bottles and film for packaging materials. Thus, forexample, 1[fi-(octadecylthio)ethyl]-3 (or 4) octadecylthio-cyclohexanewas found to be non-toxic when administered orally to mice at doses ashigh as g./ kg.

In using the compounds of the invenition a synergizing amount will beemployed together with the phenolic antioxidant. Usually from about 0.02to 0.5% by weight of the formulated polyolefin will be antioxidant andfrom about 0.02 to 1.5% weight will be synergist. Preferably the amountof synergist used will be 0.05-0.5%.

EXPERIMENTAL The compounds were evaluated as antioxidant-synergists inpolypropylene. The polypropylene test samples were prepared by dryblending 0.1% by weight of a commercial phenolic primary antioxidantsuch as Ionox 320 (a) (Shell), Irganox 101 0 (b) (Geigy) or Topanol CA(0) (ICI) and 0.1% or 0.25% by weight of the synergist into unstabilizedpolypropylene (Hercules Profax 6501 flake), extruding into inch rods,pelletizing, and hot pressing at ZOO-225 C. into 10 mil thick sheets.Unless otherwise specified all alkyl groups corresponding to R arestraight-chain alkyl.

The synergists were compared with control samples containing DSTDP instandard oven aging tests, i.e., the average hours to embrittlement of10 mil samples in a 140 C. air-circulating oven were determined. Theresults are tabulated below. The data show that the subject compoundsare highly active synergists, comparable to DSTDP. The data also show(Test Nos. 7 and 8) that simple higher alkyl sulfides such as '(n-C H Sand (n-C H S, contrary to the disclosures in British Pat. 953,447 (1964)and Italian Pat. 662,492 (1964), are not active synergists.

(a) Ionox 330 t-Cgl l'g t-C 4H9 H CH 3 PC4149 CH2 CH2 tuc ln c 3 CH (b)Irganox 1010 PC4119 PC4119 CH CH COOQH 4 C (c) Topanol CA A 3;1condensate of 3'methyl- 6-t-butylphenol and crotenaltiehyde TEST N0 .1Primary antioxidant: 0.1% Irganox 1010 $HzCH2SR Syncrgist: 0.1%

Average hours stabilization Percent hours R at 140 C. of DSTDP ll-CmHu1, 064 109 mHu 1, 139 117 n-OzoHn l, 091 112 DSTDP (Control) 976 TESTNO. 2

Primary antioxidant: 0.1% Irganox 1010 outer-123R;

Synergist: 0.25%

Average hours stabilization Percent hours B: at 140 C. STD

n-C gH 1 1, 635 n-CzoHn 325 7 DSTDP (C0ntr0l) 1,715

TEST N 0. 3 Primary antioxidant: 0.1% Irganox 1010 omom'sn,

Synergist: 0.25%

Average hours stabilization Percent hours R1 at C. of DSTDP I1-C12Hz5 1,347 I 80 n-CmHaa 1, 475 87 DSTDP (Control) 1,688 I TEST N 0. 4

Stabilizers: 0.1% Irganqx 1010 0.25% synergist Average hoursstabilization Percent hours Synergist at 140 C. of DSTDP (FHzCHzSCHzCHzCO O C12H25 1, 149 61 SCHzCHzC O 0 0121125 (A liquid product) (I) HzCHzS0121125 1, 611 86 DSTDP (Control) 1, 872

TEST NO. 5

Primary antioxidant: 0.1% Ionox 330 synergist: 0.25% '(EH2CH2SR1 Averagehours Stabilization Percent hours at 140 C. DP

synergist R1 of DST n-CisHa-l 1, 083 81 n-CzoHn 1, 243 93 DSTDP(Control) 1, 341

TEST NO. 6

Stabilizers: 0.1% Topanol CA 0.25% synergist Average hours stabilizationPercent hours at 140 C.

Synergist oi DSTDP $HzCHzSCmH33 507 100 S ieHsa DSIDP (Control)... 507

TEST NO. 7

Stabilizers: 0.1 TopanolOA 0.1% synergist Average hours stabilizationPercent hours at 140 C.

Of DSTDP 15 3025 104 13 (3H2 CHzS C EH37 004 77 S C H 1 DSTDP(Control)..... 829

TEST NO. 8

Stabilizers: 0. Topanol CA 0.25% synergist Average hours Percentstabilization hours of synergist; at 140 C. DSTDP (?H2OHzSC22-2sH45-57840 92 (See note) DSTDP (Control) 912 NOTE.-P1'epared as described aboveby 1: 2 molar reaction of (IS-(3(or 4) )-mercaptocye1ohexyl) ethnnethiolwith a commercially available (fee-cs nOrmal alph-a olefins mixture.

TEST NO. 9

Stabilizers: 0.1% Irganox 1010 0.25% synergist Average Polypropyhourssta- Percent lene sample bilization hours of No. synergist (0.25%) at140 C. DSTDP 1 l (]3HzCH:Sbranchcd 31121 727 33 S-branehed Ciallzr 2(l3I'I2CH2sn-C12Ug5 1, 611 86 S-I1Cr2l125 -S-nC1aH l C H CH3 CHQSH-C10H31 4 DLIDP 1, 603 73 5 DSTDP (Control) 2, 193

As can be seen, 2,9 bis(hexadecylthio)-p-methane (Sample 3) is about asefiective as the commercial DLTDP. Also evident is that branched higheralkyl groups (Sample 1) are relatively ineffective compared tostraight-chain alkyls.

TEST NO. 10

In oven aging tests at 140 C. as above, polypropylene containing 0.1%Irganox 1010 and 0.1% dicyclopentadiene bis(hexadecyl sulfide) showed astabilization without embrittlement about equivalent to the control of0.1% Irganox 1010 and 0.1% DSTDP.

The compounds of this invention are particularly advantageous in thatthey are resistant to hot water leaching. This property is demonstratedby the following method:

"Samples of polypropylene containing 0.1% Irganox 1010 plus 3.0%synergist were extruded and chopped to fine particle size. The samplesg.) were placed in an autoclave with 500 cc. distilled H 0 andmaintained at 100 C. for 48 hours with shaking. The sulfur content ofthe Water from each sample was determined analytically and the percentsynergist that leached from the polypropylene sample was calculated fromthe analyses. The results follow.

7 Synergist: Wt. percent leached DL'FDP 0.75 DSTDP 0.71 1 3(octadecylthi)ethyl] 3 (or 4)-octadecylthio cyclohexane 0.35

The conventional primary phenolic antioxidants which will be used withthe olefinic polymers will include both monohydric and polyhydricphenols and include bisphenols, tris-phenols and tetrakis-phenols.

Monohydric phenols useful in the invention include those disclosed inUS. 2,581,907 and include the following:

The preferred compounds of this class are those which have secondary ortertiary alkyl groups at the 2- and 6- positions and a normal alkylgroup at the 4-position, a representative of this class being2,6-di-t-butyl-p-cresol. More preferably, the normal alkyl group in the4-position is one containing from about 1 to 20 carbon atoms while thesecondary or tertiary alkyl groups in the 2- and 6-p0sitions eachcontain from about 3 to 20 carbon atoms. Any of the dialkylphenols aresuitable; particularly preferred is the 2,6-di-t-butylphenol. Thebisphenols are characterized by the general formula OH OH wherein R isan alkylidene radical of 1 to 5 carbon atoms, or is an ether orthioether group, and wherein R is an alkyl group of 1 to 12 carbon atomsand n is an integer from 1 to 3. When more than one =R' substitutent ispresent on a phenyl group, each R' can be the same or different.

Exemplary of these alkylidene-bis(alkylphenols) that may be used are2,2'-methylene-bis S-isopropylphenol) 2,2'-methylene-bis(4-methyl--isopropylphenol) 2,2-methylene-bis (4-methyl-6-t-butylphenol)2,2-methylene-bis (4-t-butyl-6-methylphenol) 2,2'-methylene-bis(4,6-di-t-butylphenol) 2,2-methylene-bis (4-nonylphenol)4,4'-methylene-bis (2,6-di-t-butylphenol 2,2'-isopropylidene-bisS-methylphenol) 4,4-methylene-bis (2-methyl-6-t-butylphenol)2,2'-ethylidene-bis (4-methyl-6-t-butylphenol) 2,2'-ethylidene-bis(4,6-di-t-butylphenol 2,2'-ethylidene-bis 4-octylphenol)2,2'-ethylidene-bis (4-nonylphenol 2,2'-isopropylidene-bis4-methyl-6-isopropyl phenol 2,2'-isopropylidene-bis 4-isopropylphenol2,2'-isopropylidene-bis 4-isopropyl-6-methylphenol2,2-isopropylidene-bis (4-methyl-6-t-butylphenol2,2'-isopropylidene-bis(4-octylphenol) 2,2'-i sopropylidene-bis(4.-nonylp henol) 2,2'-isopropyIidene-bis(4-decylphenol),2,2'-isobutylidene-bis (4-methyl-6-t-bu'tylphenol)'2,2'-isobutylidene-bis (4-nonylphenol) 4,4-butylidene-bis3-methyl-6-t-buytlphenol 1, l-thiobis- 2-naphth0l Bis 3,5-di-tert.-butyl-4-hydroxybenzyl) ether, 2,2'-thiobis-(4-methyl-6-tert.-butylphenol) and 4,4-thiobis-(5-methyl2-tert.-butylphenol)I" Of the tris-phenols useful1,3,5-trimethyl-2,4,6-tris(3,5- di-tertiary-butyl-4-hydroxybenzyl)benzene and 1,3,5-trimethyl 2,4,6-tris(3,5-di-isopropyl-4-hydroxyben2yl) benzene and the like are typical. 1 11 Tetrakis-phenols useful are exemplified by compounds such as, those ofstructure J4 where R is lower alkyl. Preferred within this group is thecompound where R is t-butyl.

The particular polyolefins which are to be treated in accord with thisinvention are any of the numerous polyolefin polymers. These willinclude the hydrocarbon polymers such as polyethylene, both conventionaland the more recent higher density materials, polypropylenepolybutene-l, poly-3-methyl-butene-1, poly-4-methylpentene-1, poly-4,4-dimethylpentene-1, polydodecene-l, and poly-3- methyl-pentene-l,polybutadiene, polystyrene, etc. It will be understood, of course, thatpolymers derived from mix tures of appropirate' olefins such asstyrene-butadiene, acrylonitrile butadiene-styrene, orethylene-propylene-dicyclopentadiene may also be treated in accordancewith the invention.

I claim:

1. Cycloalkane bis (alkylsulfides) selected from the group consistingof:

where R is straight-chain alkyl groups of from about 8 to about 30carbon atoms, R is hydrogen, methyl or ethyl groups, and R is analkylene group of from two to about four carbon atoms.

2. A compound having the structure: (l3H OH Sdodecyl wherein thedodecylthio group on theucyclohexane ring is in the 3 or 4 positionrelative to the 3 dodecylthio-ethyl group.

3. A compound of claim 2 having the name 1- [pi-(dodecylthio ethyl]-3-dodecylthiocyclohexane.

4. A compound of claim 2 having the name l-ffl- (dodecylthio) ethyl]-4-dodecylthiocyclohexane.

5. A compound having the structure: (I3HzCH Shexadecyl Shexadecylwherein the hexadecylthio group on the cyclohexane ring is in the 3 or 4position relative to the p hexadecylthioethyl group.

6. A compound. of claim 5 having the name l-[fl-(hexadecylthio) ethyl]-3hexadecylthiocyclohexane.

7. A compound of claim 5 having the name l-[p-(hexade cylthio ethyl]4hexadecylthiocyclohexane.

8. A compound having the structure:

S-octadecyl wherein the octadecylthio group on the cyclohexane ring isin the 3 or 4 position relative to the [-3 octadecylthio-ethyl group.

9. A compound of claim 8 having the name 1-[B-(octadecylthio)ethyl]3-octadecylthi0cyclohexane.

10. A compound of claim 8 having the name 1- [,B-(octadecylthio ethyl]-4-octade cylthiocyclohexane.

11. A compound having the structure:

S-eicosyl wherein the integers 1-7 identify positions on the structureand wherein the hexadecylthio groups are in the 2,5; 2,6; 3,5 or 3,6position.

References Cited Louthan: Chem. Abstracts, vol. 57 (1962), p. 16404a.

LEWIS GOTTS, Primary Examiner D. R. PHILLIPS, Assistant Examiner US. Cl.X.R.

204158 HE; 26045.75, 45.95, 609 B, 609 D Po-ww UNITED sTATEs PATENTOFFICE (569) CERTIFICATE OF CORRECTION Patent No. {59,7530 Dated ln entfl Bernard Bl Buchholz It is certified that error appears in theabove-identified patent and that said Letters Patent are herebyCorrected as shown below:

In column 2, line 9, the word "methine" should read menthane In column2, line 36 the word "fltration" should read filtration In colunn 2, line41, the formula "C H Q should read (3 4-1 8 In colunn 3, line Zl, 320should read 330 In column 4, line 31, 7 should read 77 In column 8, line31, Insert a comma between the words polypropylene poly- Signed andsealed this 25th day of July 1972.

(SEAL) Attest:

EDWARD 1mFLETCIIER,JRa ROBERT GOTTSCHALK Attesting Officer Commissionerof Patents Po-ww UNITED sTATEs PATENT OFFICE (569) CERTIFICATE OFCORRECTION Patent No. {59,7530 Dated ln ent fl Bernard Bl Buchholz It iscertified that error appears in the above-identified patent and thatsaid Letters Patent are hereby Corrected as shown below:

In column 2, line 9, the word "methine" should read menthane In column2, line 36 the word "fltration" should read filtration In colunn 2, line41, the formula "C H Q should read (3 4-1 8 In colunn 3, line Zl, 320should read 330 In column 4, line 31, 7 should read 77 In column 8, line31, Insert a comma between the words polypropylene poly- Signed andsealed this 25th day of July 1972.

(SEAL) Attest:

EDWARD 1mFLETCIIER,JRa ROBERT GOTTSCHALK Attesting Officer Commissionerof Patents UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION PatentNo. '2 my 5% I hated lQaY-rh- 99 197') Inv nt fl Bernard B. Buchholz Itis certified that error appears in the above-identified patent and that;said Letters Patent are hereby corrected as shown below:

In column 2 line 9, the word methlne" should read menthane In column 2,line 36 the word "fltration" should read filtration In colunn 2, line41, the formula "0 1-1 6 should read C 4-I8 S In colunn 3, line 21, 320should read 330 In column 4, line 31, v 7 should read 77 In column 8,line 31, Insert a comma between the words polypropylene polyv Signed andsealed this 25th day of.Ju1y 1972.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. ROBERT GOTTSCHALK Attesting Officer Commissionerof Patents

